"It is difficult to get a man to understand something, when his salary depends on his not understanding it."

Ballmer is not a Devil. Open source was costing him billions in lost Windows revenue from Google, Amazon and many other companies. Right now, with hindsight bias, we feel that the path to capitalizing on open source was OBVIOUS - it wasn't. Cloud computing wasn't a thing when Ballmer was in power - an existential crisis for the Microsoft.

The new guy Nadella is no Saint or Altruist. Right now, it's obvious business sense to embrace open source - particularly because of Azure unlike 20 years ago.

People talk about Saint Nadella and forget that Nadella's just taking the glory for Money makers that were started & financed by Ballmer - Xbox, Azure, Office 365, Hololens, Surface Pro, Windows 10...

Google which built its business on open source, embraced open source much early with Chrome & Android. However, they are doing a tactical retreat - butchering those two money makers and making key parts of them proprietary.

If Jobs were still running the show at Apple when he built NextStep, he wouldn't have embraced Unix. At that time, only broke people did open source but now big companies can go broke trying to build everything by themselves.

Just follow the money and most people are easy to understand. Google won't stop spying on people because of money. And Apple will join the fray once the financial guys can prove that they'll make more money selling customer's data.